Both
overnutrition and an incorrect nutrient balance have contributed to the rise in
obesity. Moreover, it is now clear that poor nutrition during early life augments the possibility of excess
weight gain in later years. Our aim was to determine how neonatal
overnutrition affects later responses to a
sucrose-enriched diet and whether this varies depending upon when the diet is introduced in postnatal life. Male Wistar rats raised in litters of four or 12 pups were given a 33%
sucrose solution instead of water from weaning (day 21) or postnatal day (PND) 65. All rats received normal chow ad libitum until they were euthanized on PND 80.
Body weight (BW) and food and liquid intake were monitored throughout the study. Fat mass, adipocyte morphology, serum biochemical and hormonal parameters, and hypothalamic
neuropeptide mRNA levels were measured at study termination. Neonatal
overnutrition increased food intake, BW, and
leptin levels, induced adipocyte
hypertrophy, and decreased total
ghrelin levels. The
sucrose-enriched diet increased total energy intake, adipose accrual, and
leptin,
adiponectin, and acylated
ghrelin levels but decreased BW. Most of these responses were accentuated in neonatally overnourished rats, which also had increased
insulin and
triglyceride levels. However, long-term
sucrose intake induced adipocyte
hypertrophy in rats from normal-sized litters but not in neonatally overfed rats. The results reported here indicate that neonatal
overnutrition increases the detrimental response to a diet rich in
sucrose later in life. Moreover, the timing and duration of the exposure to a
sucrose-enriched diet alter the adverse metabolic outcomes.